Key cutting jig



Aug.' l0, 1937.

J. w. FllTZ GERALD KEY CUTTING JIG l 2 SheStSI-Sheet l A Filed July 13, 1935 J. W. FlTZ GERALD KEY CUTTING JIG Filed July l5, 1955 Aug. 10, 1937.

2 sheets-sheet 2 @mig Patented Aug. 10, 1937v PATENT OFFICE KEY CUTTING JIG John W. Fitz Gerald, Milwaukee, Wis., assigner to Briggs & Stratton Corporation, Milwaukee, Wis., a corporation of Delaware Application July 13, 1935, ,Serial No. 31,247

10 Claims.

This invention relates to new and useful improvements in key cutting apparatus, and has for an object tolprovide a simple, compact, and readily :portable jig for use by lock and key service stations Vfor .quickly and accurately fitting keys to looks or duplicatingkeys.

More specically, :this invention contemplates the provision of a simple and compact jig to facilitatethe cutting of keys for the so-called double bitted locks, 'in which the Akeys are notched on both ledges of their shank.

Another objectof ,this invention is to provide a key cutting jig so constructed that ordinary inexpensive flles .canfbe used to quickly and accurately :cut the different notches with a minimum of effortandicara Another object `of this invention is to provide a keycutting jig in which the key blank can be immovably clamped in either one of two positions, so :that the notches in both edges of the blade can be accurately located with respect to the ikey shoulder and with respect to each other.

A further object of rthis invention is to provide novel means for locating the cutter guide lengthwise-ofthe key Ato present aguide of selected depth to predetermined portions of the key blank.

With the above and otherobjects in view which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as `hereinafter described and more particularly defined by the appended claims, it being understood :that such changes in the precise embodiment Aof the herein'disclosed invention may be made 'as come vwithin the scope of the claims.

AThe accompanying drawings illustrate one complete example of the physical embodiment of the :invention constructed vaccording to the best mode so far devised for the practical application of the principles thereof, and in which:

Figure *1 is a perspective View of the jig showinga key blank in position to be cut, and showing'the file guide detached;

Figure 2 is a top plan View of the jig;

Figure 3 is a front elevation view taken on the planeof the line 3-3 of Figure 2;

Figure 4 is a front elevation view similar to Figure 3, but with the key blank shown in another position;

Figure 5 is a side elevation View taken on the plane of the line 5-5 of Figure 3; and

Figure is a section view taken through Figure 5 on the planeof the line `6---6 of Figure 5.

Referring now more particularly to the accompanying drawings 5in which 'like numerals indcate like parts throughout the several views, the numeral 5 designates generally the body or base of the jig, the lower part of which is shouldered as at 6 to facilitate clamping the same upright in a vice or other mounting means (not shown).

Attached to the rear of the base 5 by means of a screw I is a clamping jaw 8 which cooperates with the rear wall of the base 5 to rigidly hold a key blank K in a position for cutting. The screw I is secured to the jaw 8 by being threaded therein and by having a lock nut 9 threaded on its outer end and bearing against the rear of the jaw. The nut 9 also serves to hold a spring blade I against the jaw for a purpose to be hereinafter described.

The screw 'I is slidably received in a bore II through the base and has a wing nut I2 threaded' on its outer end by means of which the jaw is drawn towards the base in a clamping action Disposed between the jaw and the adjoining rear wall of the base `Sand coiled about the screw 'I is a spring I3 which yieldably opens the clamp when the wing nut is loosened. The screw I is provided with a head Ill to facilitate its assembly and removal and to preclude complete removal of the wing nut.

The lower part of the jaw 8 has spaced projections I5 between which a pin I6 projects from the base to prevent the jaw from revolving around the axis of the screw. The projections I5 and an extended upper key engaging portion II give the ljaw a substantially shallow U-shape to accommodate the spring. The projections I5 also keep the jaw parallel with the rear wall of the base when the wing nut is tightened to prevent bending of the screw and possible distortion of the key blank by its being dented with an edge of the Jaw.

The upper extended key engaging portion I1 cooperates with the adjoining part of the base to securely hold the key blank in position for cutting. This adjoining part of the base is grooved as at I8 to form a ridge I9 with which the groove 2li of the key blank engages to thereby accurately locate the key blank with respect to the top of the base. Acting with the ridge I8 in positioning the key blank for cutting, are two stops or abutments 2I and 22 against which the key shoulder 23 abuts when it is inserted to define the longitudinal location of the key blank in either of two cutting positions. These stops are provided by milling the rear wall of the base at its opposite side edge portions to the depth of the groove I8.

This clamping arrangement disposes the key blank in a position between two hardened metal le guides 25 and 26 which serve to locate and determine the depth of file cuts to form the notches in the key.

The guide 25 is a substantially T-shaped block with a pin 2l projecting downwardly from its central stem portion 23. 'I'he stem portion 26 is adapted to be received in a groove 29 in the top of the base 5, the surfaces 36 and 3l of the guide bearing on the top surfaces 32 and 33, respectively, of the base. To definitely locate the guide 25 in its several positions, a plurality of holes 35 are provided in the bottom of the groove 29 for the reception of the pin 27. The groove 29 and the stem portion 28 are accurately machined, and the pin 2l' is adapted to fit closely in the holes 64 so that the guide is held rmly and accurately but freely removable in any selected position.

The top of the guide 25 has a plurality of transverse grooves, 36, 3l and 38 of different depths corresponding to the diiferent depths of the notches on the keys, and are adapted to guide a ile or similar cutting tool in cutting the various notches in thefkey blanks as will be later described.

The cutter guide 26 is in the form of a bar slidably clamped to the rear of the jaw 8 by the spring blade i6 which has its upper end portion bent abruptly forward. The forwardly bent portion is provided with a detent 46 that rides 'on the lower side of a V-shaped groove fil in the rear of the guide bar 26 and due to the compressive action of the spring blade and the shape of the groove lll, the bar is held in sliding contact with the at portions i2 of two pins 43 that project from the rear of the base 5 to provide a supportfor the guide bar that is fixed with respect to the base.

The upper edge of the guide bar 26 is stepped to provide guide surfaces 44, l5 and 46 which lie in the same horizontal planes as the bottoms of the corresponding notches 36, 31 and 38 of the guide 25. The bar 26 being slidably held, its various guide surfaces are easily brought into proper position, the end positions being determined by the engagement of two projecting pins 41 and lla with the side edges of the jaw 8, and the center position by the detent 40 engaging a depression 4S in the groove 4I.

The jig of this invention is designed primarily for the cutting of double bitted keys used in double acting six tumbler locks. l In these locks, there are three tumblers operated by one edge and three tumblers operated by the other edge of the key. Hence, to cut a key blank to any combination for locks of this character, three tumbler engaging steps must be formed on each edge of the double bitted key blank, and as the notches toprovide the tumbler engaging steps are cut by filing, it is desirable ythat there be a minimum of metal to be removed. The key blanks are accordingly furnished withv notched shanks, the notches defining raised portions staggered as to their positions on opposite edges of the shank and out of which the tumbler engaging steps are cut.

These raised portions or points have the aclditional advantage of being of such a height that they provide one of the tumbler engaging steps without any further trimming and coact with the notches cut therein to the depths determined by the three grooves 36, 3i and 38 of the guide 25 to provide the key with the tumbler engaging steps at four different heights.

Codes for the keys and locks of this type are shown in two parts in the following manner:

L ET.

the numerals referring to the diierent depths of the tumbler engaging steps, the number 1 depth being the full height of the raised points of the blank and the others being successively deeper notches in these raised portions as determined by the grooves 36, 31 and 38, indicated by the numerals 2, 3 and 4 on the front face of the depth guide 25.

The R code is always cut with the key blank in the jig with its head to the right and the cuts are made in order from the head of the blank to its tip or from right to left. The positions of the cuts along the length of the blade are indicated by the lines 50 on the upper front face of the base which also has the letters L and R delineated thereon to clearly indicate the left and right sides of the jig.

The L code is always cut With the key blank in the jig with its head tothe left. The cuts are made in order from the head to the tip of the blank or from left to right.

Obviously, this depth guide 25 must be located in correct position for each cut, and as noted hereinbefore, it is secured in any selected position by the engagement of its pin in one of the holes in the bottom of the groove. The guide bar 26 also must be properly located by sliding it to a position at which the selected depth of the guide 25 is opposite a corresponding step on the bar 26. The adjustment of the bar 26 is ak simple matter as its respective depth positions while'not indicated by numbers lare in the same sequence as the depth numbers on the guide 25.

In using the jig to cut a blank to the combina'- tion noted hereinbefore, ythe following procedure is followed.

First the jig is clamped in a vise or other suitable support. The key'blank is then inserted with the key head to the right. Care. must be' taken to push the blank all the Way in until its shoulder engages the adjacent Stop.' With the blank properly located, the wing nut is tightened to secure the same to the base. i'

The first cut in this vR combination is number 4. Hence, the guide 25 is moved'to a position at which its number 4 depth (groove 38) is in line:

with the rst cut indicator line 50. The guidebar 26 is then pushed to the left so that its lowest step is in line with the number 1 ling position.'

The actual filing is then done to form the cut in the key blank to the depth and shape dened by the groove 38 in the guide 25.

For the second cut, the depth guide 25 is placed so that depth number 2 (groove 36) is in line with' the central indicator line 50 and the filing guide bar 26 is moved all the way to the right so that its highest or number 2 position is in` operative position. The necessary notch is then led into f the key as before.

nection with the accompanying drawings, it will be readily apparent to those skilled in the vart to which this invention appertains, that this invention provides a simple, compact tool for insuring proper cutting of the double bitted keys to fit any given combination in a double bitted six tumbler lock,

What I claim as my -invention is:

1. A key cutting jig lof the character :described comprising a base, spaced fixed datum surfaces carried by the base, means for clamping a `key blank to the base in a iixed position with respect to said datum surfaces and disposed :between the same, and guides resting onsaid fixed datum surfaces so as to be disposed at oppositesides `of the key blank and in definite fixed relation lthereto, said guides having stepped gauging `surfaces adapted for guiding a cutting tool by direct contact of the tool with said gauging surfaces and being movable von said datum surfaces so `as to enable the disposition of any selected gauging surface opposite any selected portion of the key blank while it is clamped to the base.

2. A key cutting jig of the character described comprising a base, a fixed datum surface on the base, means for clamping a key blank to the base in a predetermined fixed position with respect to said datum surface, a guide for guiding a cutting tool in the notching of the blank, said guide resting on the datum surface and having stepped gauging surfaces at different distances from the datum surface adapted to guide the cutting tool by direct contact of the tool with the gauging surfaces, and means entirely independent of the key blank clamping means for locating and holding the guide at any of a number of predetermined positions on the datum surface with respect to the length of the blade of the key blank so as to enable any selected gauging surface to be held opposite any of a number of predetermined locations in the length of the blade to enable any combination of notches to be cut into the key blade without removing the blank.

3. A key cutting jig of the character described comprising two spaced adjustable guides. each having a bottom upon which it rests and each having stepped gauging surfaces at the top thereof located at different heights from the bottom, said gauging surfaces being adapted to guide a le in the formation of a cut by having the le rested directly thereon, fixed datum surfaces with which the bottoms of the guides engage and by which the guides are directly supported, means for holding the guides in any of a number of definite positions on said datum surfaces, and other means for holding a key blank in a predetermined fixed position with respect to said datum surfaces and between said guides, said two means being entirely independent of each other so that the guides may be adjusted while the key blank is held immovable.

4. A key cutting jig of the character described comprising a base, means for removably clamping a key blank to the base in a xed position with respect thereto and with one edge of its blade exposed so as to be conveniently hand led, a fixed datum surface on the base in straight line parallel relationship with respect to the 1ongitudinal axis of a key blank in position, a cutter guide having a guideway in its top surface adapted to directly receive and guide a cutting tool in the formation of a notch in the exposed edge portion of the key blank, said cutter guide resting directly on the datum surface and being movable to different positions thereon along the length of the key blank, and means entirely independent of the key blank clamping means for positively locating said guide at any of a number of predetermined fixed positions on said datum surface along the length of the exposed blade so as to selectively dispose the guideway at corresponding locations in the length of the key blank blade.

5. A key cutting jig of the character described comprising a base having spaced datum surfaces, means for readily removably clamping a key blank to the base in a xed position between said datum surfaces and with an edge of its blade projecting above said datum surfaces to be readily accessible for hand filing, and spaced adjustable guides resting on the datum surfaces to be disposed at opposite sides of a key blank in Yposition to be cut, said guides having stepped gauging surfaces at different distances from the datum surfaces each of which is positionable at any of a number of predetermined fixed locations with respect to the length of the key blade.

6. In a key cutting jig of the character described, a base having a fixed datum surface, clamping means for securing a key blank to the base with an edge portion of its blade projecting above the datum surface, a cutter guide for directly receiving and guiding a hand tool in the formation of notches in said edge portion of the key blank, said cutter guide resting on the datum surface, and readily disengageable means on the base and said guide for readily detachably holding and locating the guide in any of a number of fixed locations on the datum surface with respect to the length of the blade, said means being entirely independent of the clamping means so that any selected guiding surface may be positioned opposite any one of a number of locations in the length of the key blade.

'7. In a key cutting jig to facilitate the cutting of notches in the edges of a double bitted key, complementary clamping jaws to grip a key blank to be cut with one edge portion of its blade projecting above the tops of the jaws, a horizontal rib projecting from the clamping face of one of the jaws for engagement in a longitudinal groove in the blade of the key blank to thereby accurately locate the key blank with respect to the tops of the jaws, both ends of the rib being unobstructed and accessible to enable sliding engagement of the key blank with the rib from either end thereof, and said longitudinal groove in the key blank being centrally disposed so that by engaging the key blank from opposite ends of the rib both edges may be properly positioned for cutting, and stops on one of the jaws engageable by shoulders on the key blank for dening the endwise position of the blank.

8. In a key cutting jig of the character described, complementary jaws adapted to grip a key blank therebetween with an edge portion of its blade projecting above the upper faces of the jaws to be accessible for hand ling, a depth gauge mounted on the top face of one jaw for guiding and determining the depth of the cut made in the edge of the blank by a cutting tool, an auxiliary guide bar adjustably mounted on the other jaw to cooperate with said depth gauge, and means carried by the first named jaw for positively holding the guide bar in predetermined fixed relationship With respect to said first named jaw and consequently the depth gauge.

9. In a key cutting jig of the character described, a solid base adapted to be clamped in a vice, a clamping jaw coacting with the upper portion of the base to readily removably clamp a key blank in position to be cut With one edge of its blade projecting above the top of the base, '5 means for drawing the clamping jaw toward the base in clamping relationship, the top of the base having a transverse groove parallel with the blade of the key blank clamped in position, and a guide for guiding and determining the '10 depth of the cut made in the key blank blade by a hand le, said guide comprising a block having a part snugly tting said transverse groove so as to be held thereby against sidewise movement with respect to the key blank, said block having 1f its upper surface formed with a plurality of different depth guideWays, and cooperating means on said block and the base for positively holding the block in any of a number of predetermined positions along the length of the blade 20 of the key blank so as to position any one of its plurality yof guideways opposite any selected portion of the key blank blade at which a tumbler engaging step is to be located.

disposed at different depths so as to be located at different heights from the datum surface, and means for readily detachably holding the cutter guide in any of a number of predetermined xed locations along thelength of the key blade so as to enable the cutting of a notch of any of said diierent depths in any selected portion of the blade to thus enable the formation of any combination of notches in the key blank Without disturbing the position of the blank.

JOHN W. FITZ GERALD. 

